Push to start timer

ABSTRACT

A timer having switches actuated by motor powered cam or other means and having a shaft and a control knob therefor that can be rotated manually to set the timer and further having a timer start switch, the control knob being secured to a plunger that is rotatably keyed to the shaft but axially movable relative thereto, and linkage operative from the plunger to actuate the timer start switch only upon axial displacement of the plunger.

[ 51 June 5,1973

'iUni-ted" States Patent 1 Simmons et al.

[541 PUSH To START TIMER 2,971,143 2/1961 Stilwell, Jr. .....................200/38 R X 3,264,441 8/1966 Jenkins................... .200/38 R X Inventors: Harold T. Simmons; Richard E.

Pervorse, both of Elizabethtown,

Assignee: McGraw-Edison Company, Elgin,

ABSTRACT A. timer having switches actuated by motor powered cam or other means and having a shaft and a control knob therefor that can be rotated manually to set the timer and further having a timer start switch, the con- [22] Filed: Dec. 27, 1971 [21] Appl. No.: 212,139

I trol knob being secured to a plunger that is rotatably ....200/33 R, 200/38 R, 200/38 A keyed to the shaft but axially movable relative thereto, [51] Int. Cl...;...... and linkage operative from the plunger to actuate the [52] US. Cl.

......H0lh 3/02, HOlh 43/00 [58] Field of Search................

200/33 R, 38 R, 38 timer start switch only upon axial displacement of the plunger.

3 Claims, 5 Drawing Figures I References Cited PUSH TO START TIMER In many appliances, such as washing machines, dryers, ovens or the like, it is common to have a motor powered timer sequentially operate switches that are in appropriate circuits to give a desired operating cycle. The timer is commonly set manually by rotating a knob which physically rotates a cam cluster, for example, whereupon the motor drives the cam cluster back to actuate the switches. Safety specifications frequently require that such appliances do not start until and only upon the momentarily closing of a separate start switch.

This invention relates to, andan object of this invention is to provide, a timer having a cluster of sequentially operated switches and a single control knob which upon rotation thereof sets the timer and further which upon axial displacement thereof starts the timer.

Specific advantages and features of this invention will bemore fully understood and appreciated after reviewing the following specification, the accompanying drawing forming a part thereof, wherein:

FIG. 1 is a perspective view, partly broken away for clarity of disclosure, showing the subject invention as used in a first embodiment timer;

FIG. 2 is a sectional view, as seen generally from line 2..2 in FIG. 1, showing the start switch contact means of the timer;

" FIG. 3 is a sectional view, as seen generally from line 3-.3 in FIG. 1, showing the control knob connection and start switch actuating linkage;

FIG. 4 is a plan view of the operating cams and switch contacts used in the timer of FIG. 1; and

FIG. 5 is a sectional view, similar to FIG. 2, but .of a second embodiment of the timer invention.

FIG. 1 illustrates a timer having a synchronous motor in housing 12 with the motor output being connected through a reduction gear train in the housing 14. The powered output shaft 16 from the gear train extends into case 18 and is geared through a slip clutch 17 to shaft 19 supported in the case. The case 18 houses a plurality of switches 21 and 23 disposed adjacent and actuated by cams and 22 respectively, keyed to and rotated by shaft 19.

'The switches 21 and 23 are comprised of a resilient leaf 24 secured at terminal 26 relative to the case and having two arms extending from the secured center, and separate resilient leafs 27 and 29 secured relative to the case at terminals 28 and 30 respectively, where the switch contacts are located at the free ends of the leafs. The leaf terminals extend through the case (See FIG. 2 as a typical construction) to provide for connection with external conductors (not shown) which in turn are directed in proper circuits to be controlled.

Each arm of leaf 24 includes a cam follower 35 and 37' which engages its cam 20 and 22 respectively, and since each leaf arm is normally flexed against the cam, the cam contour determines when the contacts are opened and closed. By appropriate location of the switch closing high spots and switch opening low spots on any cam, the desired open close sequence can be obtained over one revolution of the cam; and each cam and its switch can provide an independent operating circuit during the same cam revolution. Although only two cams and switches are shown, typically four or more cams would be keyed to the shaft each spaced apart axially along the shaft and each cam would operate a separate switch.

A second resilient leaf 40 is also secured to the case 18 at the mounting terminal 26 and has a free end contact 42 that cooperates with contact 43 on aleaf 44 which is staked to the case at terminal 46 (as shownin FIG. 2). The terminal 46 would provide for connection with an exterior conductor (not shown) that together with the exterior conductor from terminal 26 would be connected in a starting circuit for the timer motor. These contacts 42 and 43 thereby provide a start control switch 47. The start circuit (not shown) might for example include a holding relay that is energized by momentary closing of the start switch 47 and is held engaged by 'one of the other timer switches which thereby releases the relay after the time cycle has run out to stop the timer motor.

The start switch leaf 40 is received in a slot in a plunger 50 supported at its opposite ends 52 and 54 within openings on the case. The plunger is thus restrained to reciprocate axially in a direction parallel to the shaft 19, but such movement is effective to open and close the start switch. Coil compression spring 56 normally holds the plunger where the enlarged shoulder 58 engages the removable cover plate 60 of the case whereat the switch 47 is open, whilethe plunger can be moved against the bias of the spring to close the switch 47. Y

Referring now to FIG. 3, a stem 66 is slidablyreceived in an open bore of shaft 19, and a coil compression spring 68 is confined between the shaft and stem effective to bias the stem outwardly relative to the shaft; A disc 69 is secured to the stem 66, such as in a recess therein, and rides within open slots 70 in the shaft 19; which disc both keys the stem and shaft to! gether rotatably and limits the axial shifting of the stem within the shaft. The shaft 19 has a pair of separated grooves located on opposite sides of the cover plate 6.0, and snap springs 72 are fitted therein to hold the shaft axially relative to the case. A control knob 74 is secured to the stem suitable to be gripped for manual rotation and/or axial depression. Wire spring 78 fits into an opening in the plunger 50 and is thereby united to the plunger and also extends across the case under the disc .69 and is hooked over and restrained on shoulder 80 in the case 12. The spring normallyis unflexed although it is proximate the disc when the plunger is in its upper extended position and the switch 47 is open. However, upon depression of the control knob 74, the disc engaging the wire shifts the plunger axially which in turn closes the switch contacts 42 and 43.

The operation of the timer is believed quite evident. The timer can have a visible dial face or the like which might indicate the time sequence either in minutes or invthe particular desire cycle of the appliance to which the timer relates, so that control knob 74 'is rotates to set the timer in the position desired. Thereafter the knob is depressed and the wire element 78 transmits this axial knob movement to'the switch plunger 50'to close the start switch 47 and begin operation of the timer. The knob can be depressed in any set position of the timer, although the separate start switch requires that the operator perform an additional step over and above merely setting the timer before'the timer actually begins. This also satisfies the safety code that provides that-once the timer stops, as for example upon the opening of the dryer door, it is necessary to depress the start control after the door is closed to again start the timer.

FIG. 5 shows an alternate embodiment start switch 47a which is self contained. In this regard the switch 47a would include a housing 88 secured to the case such as by brackets 90 and the switch contacts (not shown) are located in the housing. A plunger 92 extends from the switch housing and lines up with the plunger 50a and is actuated by axial movement of this plunger. External terminals 93 and 94 are provided for connection to suitable conductors to the start control circuit. All other aspects of the timer can be similar, except the previously provided start switch 47 and the components therefor are eliminated and substituted by the self contained switch 47a.

It is thus noted that the disclosed invention not only provides a ready means of rotatably setting a timer but also allows the simultaneous initiation of the timer cycle itself by axial displacement of the same control knob.

What is claimed is:

1. In a timer having a frame and a shaft rotatably supported therein, cam'elements supported on and rotated with the shaft, switches supported by the frame and located adjacent respective cam elements adapted to be selectively actuated thereby upon rotation of the shaft, a stern telescoped relative to the shaft and means allowing limited axial stem displacement between spaced extreme positions relative to the shaft while also rotatably keying the stem and shaft together, and manual control knob means keyed to the stem, the improvement comprising a secondary switch supported by the frame and having two operating conditions, a plunger supported in the frame to reciprocate in the same axially direction as the stern and stop means limiting the plunger displacement to between two opposite positions, said plunger being located adjacent thesecondary'switch and effective in one of said opposite positions to allow the secondary switch to assume one'of said operating conditions and effective upon travel from this one opposite position toward the other of the opposite positions and to a switch actuating position to shift the secondary switch to its other operating condition, a compression spring normally biasing the plunger to said one opposite position thereof, and an elongated spring element and means coupling said spring element at one end thereof to the plunger and means coupling said spring element at the opposite end thereof tothe frame, and means coupling said spring element at an intermediate location thereof to the stem in a manner that in one extreme stem position the plunger is in the said one opposite position and being effective under flexture upon maximum axial stern displacement to the other extreme stem position to shift the plunger to the switch actuating position. i

2. A timer combination according to claim 1, wherein the secondary switch is in the form of a selfcontained switch comprised of a housing secured to the the said plunger to the one'leaf element. 

1. In a timer having a frame and a shaft rotatably supported therein, cam elements supported on and rotated with the shaft, switches supported by the frame and located adjacent respective cam elements adapted to be selectively actuated thereby upon rotation of the shaft, a stem telescoped relative to the shaft and means allowing limited axial stem displacement between spaced extreme positions relative to the shaft while also rotatably keying the stem and shaft together, and manual control knob means keyed to the stem, the improvement comprising a secondary switch supported by the frame and having two operating conditions, a plunger supported in the frame to reciprocate in the same axially direction as the stem and stop means limiting the plunger displacement to between two opposite positions, said plunger being located adjacent the secondary switch and effective in one of said opposite positions to allow the secondary switch to assume one of said operating conditions and effective upon travel from this one opposite position toward the other of the opposite positions and to a switch actuating position to shift the secondary switch to its other operating condition, a compression spring normally biasing the plunger to said one opposite position thereof, and an elongated spring element and means coupling said spring element at one end thereof to the plunger and means coupling said spring element at the opposite end thereof to the frame, and means coupling said spring element at an intermediate location thereof to the stem in a manner that in one extreme stem position the plunger is in the said one opposite position and being effective under flexture upon maximum axial stem displacement to the other extreme stem position to shift the plunger to the switch actuating position.
 2. A timer combination according to claim 1, wherein the secondary switch is in the form of a self-contained switch comprised of a housing secured to the frame and having a push type actuator in line with and actuated by the said plunger.
 3. A timer combination according to claim 1, wherein the secondary switch is of the spring leaf type comprised of a pair of controls at least one of which is carried on a spring leaf element, and this element is supported by the frame, and wherein means couples the said plunger to the one leaf element. 